1998 Fiscal Year Final Research Report Summary
Dvelopment of Intravascular Ultrasound System and Contrast Echo Agent Involving Thrombolytic Agent for the Treatment of Acute Myocardial Infarction
| Project/Area Number |
09557061
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Circulatory organs internal medicine
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| Research Institution | Kagawa Medical University |
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Principal Investigator |
MATSUO Hirohide Kagawa Medical University Second Department of Internal Medicine Professor, 医学部, 教授 (90028514)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUNAKA Toshiyuki ALOKA Laboratory, Chief, 部長, 研究職
NOZAKI Shiro Kagawa Medical University Clinical Laboratory, Research Associate, 医学部附属病院, 助手 (80243773)
MIZUSHIGE Katsufumi Kagawa Medical University Second Department of Internal Medicine Associate Profe, 医学部附属病院, 講師 (90166009)
SENDA Shoichi Kagawa Medical University Primary care Medicine, Professor, 医学部附属病院, 教授 (30145049)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Ultrasound Contrast Agent / Ultrasound / Thronbolysis / Tissue plasminogen activator / Contrast Echo Agent |
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| Research Abstract |
Background. Although the enhancement of tissue plasminogen activator (tPA) induced thrombolysis by ultrasound has been reported to be augmented by ultrasound contrast agents (UCA), few data exist regarding its process.
Objectives. We evaluated the effect of a galactose based UCA, on the efficacy of ultrasonic enhancement of tPA thrombolysis and observed serial change in acoustic property and histopathology for the implication of its process.
Method. We employed a catheter-type transducer capable of ultrasound emission in both continuous (CW) and pulsed wave (PW). The tPA thrombolysis was studied in 30 artificial white thrombus which were assorted to 4 study groups based on insonation modes and with and without UCA.Each sample was suspended in 100 mL saline in a beaker. Five minutes after tPA (8000 U) administration, ultrasound was applied for 10 minutes. For the UCA treated groups, UCA (0.25 g) was added 5 minutes after the start of ultrasound exposure. The alteration of the thrombus was monitored with echography.
Results. Weight reduction of the thrombus was -25*6% in tPA+PW and -30*7% in tPA+CW, which was significantly enhanced by UCA treatment, -40*3% (p<0.001) in tPA+PW+UCA and -43*7% (p<0.001) in tPA+CW+UCA.Area of thrombus echo image minimally decreased with ultrasound alone (-12*6% : tPA+PW, -23*11% : tPA+CW). In UCA groups, UCA induced a remarkable reduction of size (-36*3% : tPA+PW+UCA, -43*7% : tPA+PW+UCA) with a high echo intensity in the superficial layer of thrombus, where multiple cavity formation was observed by light microscope.
Conclusions. UCA markedly enhanced the effect of ultrasound on tPA thrombolysis. The altered acoustic property and corresponding histological microcavity formation in the shallow layer within the thrombus suggests that UCA augmented infiltration of tPA into the thrombus.
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